NAME

at − execute commands at a later time

SYNOPSIS

at time [ day ] [ file ]

DESCRIPTION

At squirrels away a copy of the named file (standard input default) to be used as input to sh(1) (or csh(1) if you normally use it) at a specified later time. A cd command to the current directory is inserted at the beginning, followed by assignments to all environment variables.  When the script is run, it uses the user and group ID of the creator of the copy file. 

The time is 1 to 4 digits, with an optional following ‘A’, ‘P’, ‘N’ or ‘M’ for AM, PM, noon or midnight.  One and two digit numbers are taken to be hours, three and four digits to be hours and minutes.  If no letters follow the digits, a 24 hour clock time is understood. 

The optional day is either (1) a month name followed by a day number, or (2) a day of the week; if the word ‘week’ follows invocation is moved seven days further off.  Names of months and days may be recognizably truncated.  Examples of legitimate commands are

at 8am jan 24
at 1530 fr week

At programs are executed by periodic execution of the command /usr/lib/atrun from cron(8). The granularity of at depends upon how often atrun is executed. 

Standard output or error output is lost unless redirected. 

FILES

/usr/lib/atrunexecutor (run by cron(8)). in /usr/spool/at:
yy.ddd.hhhh.∗activity for year yy, day dd, hour hhhh. 
lasttimedonelast hhhh
pastactivities in progress

SEE ALSO

calendar(1), pwd(1), sleep(1), cron(8)

DIAGNOSTICS

Complains about various syntax errors and times out of range. 

BUGS

Due to the granularity of the execution of /usr/lib/atrun, there may be bugs in scheduling things almost exactly 24 hours into the future. 

4BSD